My own domain is deepwoods.com. Because I have a website inside the firewall, I have used a static assignment in C:\WINDOWS\system32\drivers\etc\HOSTS so my local browser will open the website for maintenance. This is to circumvent a firewall restriction that prohibits internal requests for (local) external addresses.

In fact, my external IP address for *.deepwoods.com is in a static range (which, no doubt, you can lookup )

Might I suggest, therefore, that you exclude local HOSTS file lookups from your DNS resolution of a domain name? It's the same problem that every Dynamic DNS client faces; some are rather smart, and report the first routable address retrieved from an arbitrary trace-route to some friendly site (e.g., google.com). That excludes all the 10.*, 172.16.* and 192.168.* IP address ranges from being equated to the domain name in your neat program.

If you think the existing feature needs to remain, you might want to make it an Option ("Bypass LAN").